The present invention is directed to extremely thin multilayer films and their use with laminates. Such materials have a wide variety of uses, especially in the areas of limited use and disposable items.
Many products today require highly engineered components and yet, at the same time, these products are required to be limited use or disposable items. By limited use or disposable, it is meant that the product and/or component is used only a small number of times or possibly only once before being discarded. Examples of such products include, but are not limited to, surgical and health care related products such as surgical drapes and gowns, disposable work wear such as coveralls and lab coats and a personal care absorbent products such as diapers, training pants, incontinence garments, sanitary napkins, bandages, wipes and the like. All of these products can and do utilize as components, films and fibrous nonwoven webs. While both materials are often used interchangeably, films tend to have greater barrier properties, especially to liquids, while fibrous nonwoven webs have, among other things, better tactile, comfort and aesthetic properties. When these materials are used in limited use and/or disposable products, the impetus for maximizing engineered properties while reducing cost is extremely high. To this end, it is often desirable to use either a film or a nonwoven to achieve the desired results because the combination often becomes more expensive. In the area of films, there have been previous attempts to make multilayer films with reduced thicknesses. See, for example, U.S. Pat. No. 5,261,899 to Vischer wherein a three layer film is made with a central layer that comprises from about 30 to 70% of the total thickness of the multilayer film. One advantage in forming multilayer films is that specific properties can be designed into the film, and, by making the films multilayer the more costly ingredients can be relegated to the outer layers where they are most likely to be needed.
In addition, in the production of a breathable filled film it is common to employ a significant percent (by weight) of filler such as, for example, CaCO.sub.3. As is known in the art, stretching of the filled film creates a fine pore network which allows the film to continue to act as a barrier to liquids and particulate matter yet allow air and water vapor to pass therethrough. In order to obtain more uniform barrier and vapor transmission properties throughout the film it is desirable to have the filler equally distributed throughout the film. Thus, although such breathable barriers may act as a barrier to liquids and particulate matter they may themselves be a source of unwanted particles (i.e. the filler). This may be undesirable in various applications or articles employing the barrier fabric. A filled film which retains good breathability while having reduced particle fallout is therefore desirable. In this regard, there exists a continuing need for a multilayer film having outer layers with little or no filler, yet which does not significantly reduce the breathability of the multilayer film. Moreover, many filled films fail to provide good adhesion to additional layers, such as, for example, nonwoven fabrics. Multilayer films which are capable of providing good adhesion to a support fabric without loss of breathability is likewise needed.
It is therefore an object of the present invention to provide a multilayer film which can be engineered to overcome problems experienced by those skilled in the art and provide specific properties while having a very thin gauge. Another object of the present invention is to combine low gauge films with other support layers such as layers of fibrous nonwoven webs to improve processing, to increase strength, and to provide aesthetic properties. A further object of the present invention is to provide a multilayer filled film having good breathability while having improved thermal adhesion and/or reduced particle fallout. The means by which such objectives are achieved can be more fully comprehended by a review of the following specification, drawings and claims.